CN108008480B - Polarizing plate and display device having polarizing plate - Google Patents

Abstract

The polarizing plate and the display device including the same of the present disclosure absorb and disperse external impact by laminating films having different strengths. As described above, according to the present disclosure, a thin film is used instead of a thick cover window, so that a thin thickness, light weight, and low cost of the polarizing plate can be achieved. In addition, the manufacturing process is simplified and the process cost is reduced.

Description

Polarizing plate and display device having polarizing plate

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Korean Patent Application No. 10-2016-0143572 filed in the Korean Intellectual Property Office on October 31, 2016, the disclosure of which is incorporated herein by reference.

technical field

The present disclosure relates to a polarizing plate and a display device including the polarizing plate, and more particularly, to a polarizing plate suitable for absorbing external impact and a display device including the polarizing plate.

Background technique

Recently, with an increase in interest in information displays and an increase in demand for portable information media, research into a lightweight and thin flat panel display (FPD) replacing a cathode ray tube (CRT) as a related art display device has been mainly conducted and commercialize.

Specifically, among flat panel displays, a liquid crystal display device (LCD) is a device that displays images using the optical anisotropy of liquid crystals. Liquid crystal displays are excellent in resolution, color display, and image quality, so that they are actively applied to monitors of notebook computers or desktop computers.

Hereinafter, the structure of a general liquid crystal display device will be described in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view schematically showing the structure of a general liquid crystal display device.

1 , a typical liquid crystal display device includes a liquid crystal panel 10 and a backlight unit (not shown) disposed on the rear surface of the liquid crystal panel 10 to provide light to the liquid crystal panel 10 .

The liquid crystal panel 10 includes a first substrate 5 , a second substrate 15 , and a liquid crystal layer 30 formed between the first substrate 5 and the second substrate 15 .

Although not shown in detail, the first substrate 5 is a color filter substrate on which color filters are formed, and the second substrate 15 is a TFT substrate on which driving elements such as thin film transistors and pixel electrodes are formed. Further, a driving circuit unit is mounted on one side of the second substrate 15 to apply signals to thin film transistors and pixel electrodes formed on the second substrate 15 .

The polarizing plate 1 and the polarizing plate 11 are provided on the upper and lower surfaces of the liquid crystal panel 10, respectively.

In this case, the first polarizing plate 1 includes the polarizer 2 and protective layers 3 a and 3 b formed on both sides of the polarizer 2 , and the polarizing plate 1 is attached on the first substrate 5 by the adhesive 7 .

A cover window 20 is attached to the first polarizing plate 1 through a bonding agent or an air gap 8 to absorb external shocks. That is, in the related art, the shock applied from the outside is absorbed by the cover window 20 and the air gap 8 .

The cover window 20 has high strength to ensure the shock absorbing function. However, materials such as thick glass or plastic are used for the cover window, undesirably increasing the thickness, weight and processing cost of the liquid crystal display device.

The thickness of the glass of the cover window 20 is about 300 μm to 500 μm and requires chemical and physical tempering. In addition, the strength of plastic is lower than that of glass, so that the thickness of the plastic needs to be 500 μm or more, and a separate surface treatment is required to increase hardness and scratch resistance.

The thickness of the air gap 8 or the bonding agent is about 100 μm to 200 μm.

In addition, in order to join the liquid crystal panel 10 and the cover window 20, complicated joining processes such as a resin application process, a joining process using a jig, a dispersion process, a primary hardening process, a washing process, and a secondary hardening process are required. Therefore, not only process costs but also loss costs due to failures in the process may be incurred.

SUMMARY OF THE INVENTION

An object to be achieved by the present disclosure is to provide a polarizing plate suitable for absorbing external impact by laminating films and a display device including the polarizing plate.

Another object of the present disclosure is to provide a polarizing plate and a display device including the polarizing plate that realize a shock absorption function by itself rather than a cover window.

Other objects and features of the present disclosure will be described in the following configuration and claims of the present disclosure.

According to an aspect of the present disclosure, there is provided a polarizing plate including a polarizer and a first film having a low intensity and a second film having a high intensity above the polarizer.

According to another aspect of the present disclosure, there is provided a display device including a display panel in which a polarizing plate is attached to a first substrate.

According to an exemplary embodiment of the present disclosure, in the polarizing plate and the display device including the polarizing plate, the first film is positioned on the uppermost layer, the second film is positioned below the first film, and the strength of the first film is smaller than that of the second film strength.

As described above, according to the present disclosure, in a polarizing plate and a display device including a polarizing plate, a thin film is used instead of a thick cover window, so that thin thickness, light weight and reduced cost of the polarizing plate can be achieved, and The manufacturing process is simplified and the process cost is reduced.

Description of drawings

The above and other aspects, features and other advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view exemplarily showing the structure of a general liquid crystal display device;

2A and 2B are exemplary diagrams illustrating characteristics of light transmitted through a liquid crystal panel;

3 is a cross-sectional view exemplarily showing the structure of the display device according to the first exemplary embodiment of the present disclosure;

4 is an exploded perspective view schematically showing components of a polarizing plate in the display device according to the first exemplary embodiment of the present disclosure shown in FIG. 3;

5 is a cross-sectional view for explaining an external shock absorption mechanism of the polarizing plate according to the first exemplary embodiment of the present disclosure;

6A and 6B are cross-sectional views specifically illustrating the shock absorption mechanism shown in FIG. 5;

FIG. 7 is a table showing an example of impact test results of polarizing plates according to the present disclosure.

FIG. 8 is a cross-sectional view exemplarily showing a structure of a display device according to a second exemplary embodiment of the present disclosure; and

9 is a cross-sectional view exemplarily showing the structure of a display device according to a third exemplary embodiment of the present disclosure.

Detailed ways

Exemplary embodiments of a polarizing plate and a display device including the polarizing plate according to the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the present invention are shown so that those skilled in the art can easily Example embodiments of the present disclosure are implemented.

Advantages and features of the present disclosure, as well as methods for achieving the advantages and features, will be apparent by reference to the following detailed description of the exemplary embodiments, taken together with the accompanying drawings. However, the present disclosure is not limited to the following exemplary embodiments, but may be implemented in various forms. Example embodiments are provided only for complete disclosure and to fully convey the class of the disclosure to those of ordinary skill in the art to which this disclosure pertains, and which will be defined by the appended claims. The same reference numerals refer to the same elements throughout the specification. In the drawings, the size and relative sizes of layers or regions may be exaggerated for clarity of description.

When an element or layer is disposed "on" other elements or layers, the other layer or element can be directly interposed on or between the other elements or layers. In contrast, when an element is referred to as being "immediately on" or "directly on", there are no intervening elements or layers present.

Terms such as "below", "below", "lower", "above" or "higher" are spatially relative terms and may be used to describe relationship between one element or component and another element or component shown. Spatially relative terms should be understood to include different orientations of use or operation of the element in addition to the orientation shown in the figures. For example, when elements shown in the figures are turned over, elements disposed below or below another element may be disposed above the other element. Thus, the exemplary term "under" can include both an orientation of above and below.

The terms used in this specification are used to describe the embodiments rather than to limit the present invention. In this specification, the singular form also includes the plural form unless otherwise specified. The meaning of "comprising" and/or "comprising" used in this specification does not exclude the presence or Add to.

As an example of a display device, a liquid crystal display device is driven by two opposing electrodes and a liquid crystal layer formed between the opposing electrodes. The liquid crystal molecules of the liquid crystal layer are driven by an electric field generated by applying a voltage to the two electrodes.

Liquid crystal molecules have polarization properties and optical anisotropy. The polarization characteristic means that when the liquid crystal molecules are located in an electric field, the charges in the liquid crystal molecules are concentrated on both sides of the liquid crystal molecules, so that the arrangement direction of the molecules changes according to the electric field. In addition, optical anisotropy means that the path or polarization state of emitted light varies based on the elongated structure of liquid crystal molecules and the above-mentioned molecular arrangement direction, depending on the incident direction or polarization state of incident light.

Therefore, the liquid crystal display device includes a liquid crystal panel formed of a pair of transparent insulating substrates in which the electric field generating electrodes are formed of two opposing faces, and a liquid crystal layer as an essential component between the pair of transparent insulating substrates. In addition, the alignment direction of the liquid crystal molecules is artificially adjusted by changing the electric field between the electric field generating electrodes, and various images can be displayed using the transmittance of light changed at this time.

In this case, the polarizing plates are positioned above and below the liquid crystal panel. The polarizing plate can determine the transmittance of light by arranging the transmission axes of the two polarizing plates and determine the alignment characteristics of the liquid crystal by transmitting light having a polarization component matching the transmission axis.

2A and 2B are exemplary diagrams illustrating characteristics of light transmitted through the liquid crystal panel.

In this case, FIGS. 2A and 2B illustrate the driving of the liquid crystal panel in a twisted nematic (TN) mode as an example. However, the present disclosure is not limited thereto, and may be applicable regardless of liquid crystal modes, such as super TN mode (STN), vertical alignment mode (VA), in-plane switching mode (IPS), fringe field switching mode (FFS), or optical Compensated Bending Mode (OCB).

Referring to the drawings, the liquid crystal display device may mainly include a liquid crystal panel 110 and a backlight unit (not shown) that provides light from a rear surface of the liquid crystal panel.

The liquid crystal panel 110 includes a first substrate 105 and a second substrate 115 bonded to each other, a liquid crystal layer 130 is between the first substrate 105 and the second substrate 115, and the first polarizing plate 101 and the second polarizing plate 111 are attached to the first and second polarizing plates 101 and 111, respectively. A substrate 105 and a second substrate 115 are on the outer surfaces.

Although not shown in the drawings, color filters and common electrodes for realizing colors are assembled inside the first substrate 105 . In addition, a plurality of pixels and thin film transistors in which transparent pixel electrodes are formed, and the thin film transistor switches control the liquid crystal driving voltage transmitted to each pixel electrode may be assembled inside the second substrate 115 .

In addition, in the twisted nematic (TN) mode, the liquid crystal layer 130 interposed between the first substrate 105 and the second substrate 115 is aligned at 90 degrees from the first substrate 105 to the second substrate 115 in a voltage-off state The orientation angle of the s is twisted while keeping the major axis directions of the molecules parallel to the first substrate 105 and the second substrate 115 . In this case, the polarization axes of the first polarizing plate 101 and the second polarizing plate 111 may be orthogonal to each other.

Since the liquid crystal panel 110 itself does not emit light, a backlight unit that provides light to the liquid crystal panel 110 may be located on the rear surface of the liquid crystal panel 110 .

When the voltage is off in the liquid crystal panel 110, as shown in FIG. 2A, only the linearly polarized light parallel to the polarization axis of the light emitted from the backlight unit is transmitted by the second polarizing plate 111, and the rest is absorbed. Therefore, the light rotates at an orientation angle of 90 degrees while passing through the liquid crystal layer 130, so that the light is transmitted through the first polarizing plate 101 to display white.

Next, when the voltage is on, as shown in FIG. 2B , the major axes of the liquid crystal molecules of the liquid crystal panel 110 are arranged to be orthogonal to the first polarizing plate 101 and the second polarizing plate 111 , so that the liquid crystal molecules lose the 90-degree optical rotation ability . Therefore, the linearly polarized light transmitted through the second polarizing plate 111 is blocked by the first polarizing plate 101, thereby displaying black.

3 is a cross-sectional view exemplarily showing the structure of a display device according to the first exemplary embodiment of the present disclosure, and showing a liquid crystal display device as an example of the display device. However, the present disclosure is not limited to liquid crystal display devices.

FIG. 4 is an exploded perspective view schematically showing components of a polarizing plate in the display device according to the first exemplary embodiment of the present disclosure shown in FIG. 3 . In this case, as an example, FIG. 4 shows the first polarizing plate on the upper surface of the liquid crystal panel.

Referring to the drawings, the liquid crystal display device according to the first exemplary embodiment of the present disclosure includes a liquid crystal panel 110 and a backlight unit (not shown) disposed on a rear surface of the liquid crystal panel 110 to provide light to the liquid crystal panel 110 .

The liquid crystal panel 110 is an example of a display panel in which an actual image is realized, and includes a first substrate 105 , a second substrate 115 , and a liquid crystal layer 130 formed between the first substrate 105 and the second substrate 115 .

Although not specifically shown, the first substrate 105 is a color filter substrate on which color filters are formed. The first substrate 105 may include a color filter formed of a plurality of sub-color filters, a black matrix that divides the sub-color filters and blocks light transmitted through the liquid crystal layer, and a transparent common electrode that applies a voltage to the liquid crystal layer.

Further, the second substrate 115 is an array substrate in which driving elements such as thin film transistors are formed. The second substrate 115 may include a plurality of gate lines and a plurality of data lines arranged vertically and horizontally to define a plurality of pixel regions, thin film transistors serving as switching elements formed in intersection regions of the gate lines and the data lines, and A pixel electrode formed in the pixel area.

The thin film transistor may be configured by a gate electrode connected to the gate line, a source electrode connected to the data line, and a drain electrode electrically connected to the pixel electrode. In addition, the thin film transistor may include an active layer that forms a conduction channel between the source electrode and the drain electrode by a gate voltage supplied to the gate electrode.

The liquid crystal panel 110 includes a backlight unit mounted on the rear surface to provide light. This is because the liquid crystal device does not include a self-luminous element and thus requires a separate light source.

For example, any one of fluorescent lamps such as Cold Cathode Fluorescent Lamps (CCFLs), External Electrode Fluorescent Lamps (EEFLs), and Hot Cold Fluorescent Lamps (HCFLs) and Light Emitting Diodes (LEDs) may be used as the light source.

The polarizing plate 101 and the polarizing plate 111 may be provided on the upper and lower surfaces of the liquid crystal panel 110 configured as described above.

Light emitted from the backlight unit is polarized by the second polarizing plate 111 attached to the second substrate 115 . The polarization state of the light is changed while passing through the liquid crystal layer 130 , and then the light is emitted to the outside through the first polarizing plate 101 attached to the first substrate 105 . In this case, the transmittance of the light transmitted through the first polarizing plate 101 is adjusted according to the change in the polarization state of the light passing through the liquid crystal layer 130, so that an image can be realized.

The first polarizing plate 101 attached to the upper surface of the liquid crystal panel 110 includes a polarizer 102 , a protective layer 103 formed below the polarizer 102 , and first to third films 104 , 105 and 106 formed above the polarizer 102 .

The first polarizing plate 101 is a general polarizing element that transmits only light having a vibration plane in a predetermined direction among natural light having vibration planes in all directions of 360 degrees and absorbs the remaining light to obtain polarized light.

Generally, an element that separates a polarization component perpendicular to the incident plane and a polarization component parallel to the incident plane using the polarizer 102 having light absorption properties is used, and linearly polarized light and elliptically polarized light can be obtained through the polarizer 102 .

For this purpose, an appropriate material is selected according to the purpose and processed to have a film shape, thereby obtaining uniform polarization characteristics and high polarization efficiency.

For example, a polyvinyl alcohol (PVA) film treated with iodine can be used as the polarizer 102 . In addition, a cellulose triacetate (TAC) film or a polymethyl methacrylate (PMMA) film may be used as the protective layer 103 as an inner substrate for protecting the PVA film, wherein the cellulose triacetate film has not only size and Modified stability and abrasion resistance, but also with excellent clarity, UV absorbability and durability, polymethyl methacrylate films are examples of acrolein-based. However, the present disclosure is not limited thereto.

The first polarizing plate 101 configured as described above may be attached to the first substrate 105 by the adhesive 107 .

In this case, in the first polarizing plate 101 according to the first exemplary embodiment of the present disclosure, instead of the cover window of the related art, the first to third films 104 having different intensities are stacked over the polarizer 102 , 105 and 106 to absorb and disperse external shocks.

The first to third films 104 , 105 and 106 may be formed to be thin so as to be integrated with the first polarizing plate 101 as an outer base material of the first polarizing plate 101 .

As described above, instead of a thick cover window, the first to third films 104 , 105 and 106 are used, so that thin thickness, light weight and reduced cost of the first polarizing plate 101 can be achieved.

Further, when the polarizing plate 101 is attached to the liquid crystal panel 110, the first to third films 104, 105 and 106 are attached at the same time. Therefore, the manufacturing process is simplified and the process cost is reduced compared to the related art cover window bonding process. That is, in the related art, after the polarizing plate is attached to the liquid crystal panel, the cover window bonding process is additionally performed. In contrast, according to the present disclosure, when the polarizing plate is manufactured, the films are bonded to each other through a roll-to-roll process, so that the polarizing plate can be simply attached to the liquid crystal panel.

To this end, in the first polarizing plate 101 according to the present disclosure, the first film 104 having low strength and the second film 105 having high strength are stacked over the polarizer 102 . In this case, in the first polarizing plate 101 according to the first exemplary embodiment of the present disclosure, as an example, the first film 104 having low strength and the second film 105 having high strength are laminated on the polarizing plate above the device 102 only once, but the present disclosure is not so limited.

In this case, the first film 104 having low strength is laminated over the second film 105 having high strength to effectively absorb external shocks, and it is possible to interpose between the second film 105 and the polarizer 102 Strength of the third membrane 106 .

The first film 104, which is the uppermost layer, absorbs (attenuates) the external shock to transmit the shock to the lower part, and the second film 105 under the first film disperses and absorbs the damped external shock.

Hereinafter, an external shock absorption mechanism of the polarizing plate according to the present disclosure will be described in detail with reference to the accompanying drawings.

5 is a cross-sectional view for explaining an external shock absorption mechanism of the polarizing plate according to the first exemplary embodiment of the present disclosure.

6A and 6B are cross-sectional views specifically illustrating the shock absorption mechanism shown in FIG. 5 .

Referring to FIGS. 5 and 6A , an external impact applied to the first polarizing plate 101 may be absorbed by the first film 104 as the uppermost layer to be transmitted to the lower portion.

In this case, the first film 104 may be configured by a low-strength film, preferably a low-strength and high-hardness film.

As described above, according to the present disclosure, since the uppermost layer of the first polarizing plate 101 is configured of the low-strength film, external impact is attenuated to be transmitted to the lower portion. In this case, if the uppermost layer is configured with a high-strength film, the impact is not absorbed (or attenuated), so that the high-strength film may be damaged (broken or broken).

The external shock applied to the first film 104 having low strength is absorbed (attenuated) in a predetermined area (a relatively narrow area) of the first film 104, and the damped shock is transmitted to the lower part.

As the low-strength film, TAC, acrolein-based, polyethylene terephthalate (PET) or cycloolefin polymer (COP) can be used. The tensile/flexural modulus of elasticity of the first film 104 may be 10 to 500 MPa, preferably, 100±10 MPa. In addition, the thickness of the first film 104 may be 50 to 150 μm, preferably, 100±10 μm.

As described above, the first membrane 104 is a surface coating with high hardness, scratch resistance, and fouling resistance, and serves as a support layer. In addition, when an impact is applied, the first film 104 serves as a cushion, and is supported by the second film 105 having high strength disposed thereunder to suppress direct damage to the surface treatment layer having high hardness.

Next, referring to FIGS. 5 and 6B , the external impact reduced by the first film 104 having low strength is dispersed and absorbed by the second film 105 disposed under the first film 104 .

In this case, the second film 105 may be configured by a high-strength film, preferably a high-strength and low-hardness film.

As described above, according to the present disclosure, since the second film 105 having a high strength is positioned below the first film 104 having a low strength, external shocks attenuated by the first film 104 can be dispersed and absorbed. In this case, the impact remaining after absorption is widely dispersed and diffused to suppress damage to the underlying layer.

As a high-strength film, a high-strength polymer material such as polyimide (PI) or tempered acyl or polycarbonate (PC) can be used. The tensile/flexural modulus of elasticity of the second film 105 may be 1000 to 50000 MPa, preferably, 10000±1000 MPa. In addition, the thickness of the second film 105 may be 50 to 150 μm, preferably, 100±10 μm.

In this case, the second film 105 having high strength is the main layer for dispersing and absorbing the impact, and widely dispersing and diffusing the impact remaining after the absorption to suppress damage to the lower layer. When the second membrane 105 is configured of a sponge-like low-strength membrane instead of a high-strength membrane, the remaining impact is not dispersed, so that the underlying layer may be damaged.

As described above, the first polarizing plate 101 according to the first exemplary embodiment of the present disclosure can absorb external impact by laminating the first film 104 with low strength and the second film 105 with high strength over the polarizer 102 .

In this case, in order to additionally absorb shock, a third film 106 having a low strength may be inserted between the second film 105 and the polarizer 102 .

The third film 106 is a low strength film and may be of substantially the same material and thickness as the first film 104 .

The third film 106 with low strength additionally absorbs (eliminates) the impact and also serves as a protective substrate for the polarizer 102 .

As described above, the first film 104 having low strength needs to be laminated on the uppermost layer of the first polarizing plate 101 . Basically, the first film 104 with low strength and the second film 105 with high strength under the first film 104 need to be laminated at least once. Therefore, the first film 104 with low strength and the second film 105 with high strength may be alternately laminated at least twice according to the level of impact resistance required.

FIG. 7 is a table showing an example of impact test results of polarizing plates according to the present disclosure.

In this case, as an example, Figure 7 shows the impact test results when balls of 22 g and 130 g were dropped from heights of 10, 30, 60 and 100 cm.

In this case, in Comparative Example 1, a general polarizing plate in which TAC is laminated as an external base material on a polarizer is exemplified, and in Comparative Example 2, a high-strength polyimide film is exemplified in a comparative example. 1's polarizing plate above the polarizing plate.

In the experimental example, a polarizing plate in which a polyimide film having high strength and a TAC film having low strength are laminated over the polarizing plate of Comparative Example 1 is exemplified.

In this case, the liquid crystal panel was attached to the lower portion of the polarizing plate using an adhesive, and TAC was used as an inner base material. The thicknesses of the liquid panel, adhesive, TAC and PVA used for testing were about 600 μm, 13 μm, 20 μm and 12 μm, respectively. Moreover, the thickness of TAC which is the external base material of the comparative example 1, the comparative example 2, and the experimental example was about 25 micrometers, and the thickness of the high-strength polyimide film of the comparative example 2 was about 60 micrometers. In addition, the thicknesses of the high-strength polyimide film and the low-strength TAC film of the experimental example were about 50 μm and 60 μm.

Referring to FIG. 7 , in Comparative Example 1 of a common polarizing plate, when a ball of 22 g was dropped from the upper portion, bright spot defects were generated in heights of 10 cm and 30 cm in all five tests.

In addition, in the height of 60 cm, during the five tests, a bright spot defect was generated in four tests, and "broken" (liquid crystal panel) was generated in one test. During all three tests at a height of 100 cm, the liquid crystal panel shattered.

When a ball of 130 g was dropped from the upper part, the liquid crystal panel was broken in a height of 10 cm.

Next, in Comparative Example 2 in which the high-strength polyimide film was laminated, when a ball of 22 g was dropped from the upper part, in the height of 10 cm during the five tests, no bright spot defect was generated in four tests, But at a height of 30 cm, bright spot defects were produced in all five tests.

Furthermore, in a height of 60 cm, during five tests, bright spot defects were generated in two tests, and "cracking" (breaking of the surface layer) occurred in three tests. At 100 cm height, the liquid crystal panel broke in all five tests.

When a ball of 130 g was dropped from the upper part, the liquid crystal panel was broken in a height of 20 cm.

Next, in the experimental example in which the polyimide film with high strength and the TAC film with low strength were laminated, when a ball of 22 g was dropped from the top, in heights of 10 cm, 30 cm, 60 cm, and 100 cm , there were no bright spot defects and no "shattering" in all five tests.

In addition, when a ball of 130 g was dropped from the top, the liquid crystal panel was not broken up to 80 cm.

As mentioned above, external shocks are absorbed by laminating films with different strengths over the polarizer. In this case, a film with low strength is laminated on the uppermost layer, and a film with high strength is laminated below it.

In order to completely absorb the external impact, the present disclosure may be applied to a case where a film having a low strength and a film having a high strength are alternately laminated a plurality of times, which will be described in detail through the second exemplary embodiment of the present disclosure.

8 is a cross-sectional view exemplarily showing a structure of a display device according to a second exemplary embodiment of the present disclosure, in which a liquid crystal display device is shown as an example of the display device. However, as described above, the present disclosure is not limited to liquid crystal display devices.

The display device according to the second exemplary embodiment of the present disclosure shown in FIG. 8 may be composed of the same film according to the above-described first embodiment of the present disclosure, except that the film having low strength and the film having high strength are alternately laminated multiple times. The display device of an exemplary embodiment is configured with substantially the same configuration.

8 , the liquid crystal display device according to the second exemplary embodiment of the present disclosure includes a liquid crystal panel 210 and a backlight unit (not shown) disposed on a rear surface of the liquid crystal panel 210 to provide light to the liquid crystal panel 210 .

In the liquid crystal panel 210, an actual image is realized. The liquid crystal panel 210 includes a first substrate 205 , a second substrate 215 , and a liquid crystal layer 230 formed between the first substrate 205 and the second substrate 215 .

The polarizing plate 201 and the polarizing plate 211 may be provided on the upper and lower surfaces of the liquid crystal panel 210 configured as described above.

Light emitted from the backlight unit is polarized by the second polarizing plate 211 attached to the second substrate 215 . The polarization state of the light is changed while passing through the liquid crystal layer 230 , and then the light is emitted to the outside through the first polarizing plate 201 attached to the first substrate 205 . In this case, the transmittance of the light transmitted through the first polarizing plate 201 is adjusted according to the change in the polarization state of the light passing through the liquid crystal layer 230, so that an image can be realized.

The first polarizing plate 201 attached to the upper surface of the liquid crystal panel 210 includes a polarizer 202 , a protective layer 203 as an inner substrate formed under the polarizer 202 , a third film 206 , and a plurality of polarizers 202 formed over the polarizer 202 . A first film 204 and a plurality of second films 205 .

The first polarizing plate 201 may be attached to the first substrate 205 by an adhesive 207 .

In this case, in the first polarizing plate 201 according to the second exemplary embodiment of the present disclosure, instead of the cover window of the related art, the first film 204 and the second film 205 having different strengths are laminated on the polarizer 202 above to absorb and disperse external shocks. That is, the first film 204 with low strength and the second film 205 with high strength may be alternately laminated at least twice according to the level of impact resistance required.

The first to third films 204 , 205 and 206 may be formed to be thin so as to be integrated with the first polarizing plate 201 as an outer base material of the first polarizing plate 201 .

As described above, instead of a thick cover window, the first to third films 204, 205, and 206 are used, so that thin thickness, light weight, and reduced cost of the first polarizing plate 201 can be achieved.

Further, when the polarizing plate 201 is attached to the liquid crystal panel 210, the first to third films 204, 205 and 206 are attached at the same time. Therefore, the manufacturing process is simplified and the process cost is reduced compared to the related art cover window bonding process.

For this reason, in the first polarizing plate 201 according to the second exemplary embodiment of the present disclosure, the first film 204 having a low strength and the second film 205 having a high strength are alternately stacked over the polarizer 202 for a plurality of Second-rate.

In this case, in order to effectively absorb the external impact, the first film 204 with low strength is laminated on the uppermost layer, and the second film 205 with high strength is laminated under the first film 204, and may be multiple times Perform alternate stacking. Furthermore, a third film 206 having low strength may be interposed between the second film 205 as the lowermost layer and the polarizer 202 .

The first film 204, which is the uppermost layer, absorbs (attenuates) the external shock to transmit the shock downward, and the second film 205 under the first film disperses and absorbs the damped external shock. Such an external shock absorption mechanism is applied to the first film 204 and the second film 205 which are laminated in the same manner below, to completely absorb the shock.

As described above, the first film 204 may be configured by a low-strength film, preferably a low-strength and high-hardness film.

As the low-strength film, TAC, acrolein-based or polyethylene terephthalate (PET) or cyclic olefin polymer (COP) can be used. The tensile/flexural modulus of elasticity of the first film 204 may be 10 to 500 MPa, preferably, 100±10 MPa. In addition, the thickness of the first film 204 may be 50 to 150 μm, preferably, 100±10 μm.

The second film 205 may be configured by a high-strength film, preferably a high-strength and low-hardness film.

As the high-strength film, a high-strength polymer material such as polyimide (PI) or tempered acyl or polycarbonate (PC) can be used. The tensile/flexural modulus of elasticity of the second film 205 may be 1000 to 50000 MPa, preferably, 10000±1000 MPa. In addition, the thickness of the second film 205 may be 50 to 150 μm, preferably, 100±10 μm.

In this case, in order to additionally absorb shock, a third film 206 having a low strength may be inserted between the second film 205 as the lowermost layer and the polarizer 202 .

The third film 206 is a low strength film and may be of substantially the same material and thickness as the first film 204 .

The third film 206 with low strength additionally absorbs (eliminates) the impact and also serves as a protective substrate for the polarizer 202 .

According to the present disclosure, in order to effectively absorb the impact, a bonding agent or an adhesive may be interposed between the first to third films, which will be described in detail through the third exemplary embodiment of the present disclosure.

9 is a cross-sectional view exemplarily showing the structure of a display device according to a third exemplary embodiment of the present disclosure, in which a liquid crystal display device is shown as an example of the display device. However, as described above, the present disclosure is not limited to liquid crystal display devices.

The display device according to the third exemplary embodiment of the present disclosure shown in FIG. 9 may be used in combination with the present disclosure as described above, except that the bonding agent or adhesive is interposed between the first to third films. Basically the same configuration of the display device of the first exemplary embodiment of the content is configured.

9 , the liquid crystal display device according to the third exemplary embodiment of the present disclosure includes a liquid crystal panel 310 and a backlight unit (not shown) disposed on a rear surface of the liquid crystal panel 310 to provide light to the liquid crystal panel 310 .

In the liquid crystal panel 310, an actual image is realized. The liquid crystal panel 310 includes a first substrate 305 , a second substrate 315 , and a liquid crystal layer 330 formed between the first substrate 305 and the second substrate 315 .

The polarizing plate 301 and the polarizing plate 311 may be provided on the upper and lower surfaces of the liquid crystal panel 310 configured as described above.

The first polarizing plate 301 attached to the upper surface of the liquid crystal panel 310 includes a polarizer 302 , a protective layer 303 as an inner substrate formed below the polarizer 302 , a plurality of first to third formed above the polarizer 302 Membranes 304 , 305 and 306 .

The first polarizing plate 301 may be attached to the first substrate 305 by an adhesive 307 .

In the first polarizing plate 301 according to the third exemplary embodiment of the present disclosure, substantially similar to the first exemplary embodiment of the present disclosure as described above, the first film 304 having low strength and having High strength second films 305 are alternately laminated over polarizers 302 . In this case, in the first polarizing plate 301 according to the third exemplary embodiment of the present disclosure, as an example, the first film 304 with low strength and the second film 305 with high strength are in the polarizer The layer above 302 is only once, but the present disclosure is not so limited.

In this case, the first film 304 having low strength is laminated on the second film 305 having high strength to effectively absorb external shocks, and it is possible to interpose between the second film 305 and the polarizer 302 the second film 305 having low strength Strength of the third membrane 306 .

The first film 304, which is the uppermost layer, absorbs (attenuates) the external shock to transmit the shock downward, and the second film 305 under the first film disperses and absorbs the damped external shock.

As described above, the first film 304 may be configured by a low-strength film, preferably a low-strength and high-hardness film.

As the low-strength film, TAC, acrolein-based or polyethylene terephthalate (PET) or cycloolefin polymer (COP) can be used. The tensile/flexural modulus of elasticity of the first film 304 may be 10 to 500 MPa, preferably, 100±10 MPa. In addition, the thickness of the first film 304 may be 50 to 150 μm, preferably, 100±10 μm.

The second film 305 may be configured from a high strength film, preferably a high strength and low hardness film.

As the high-strength film, a high-strength polymer material such as polyimide (PI) or tempered acyl or polycarbonate (PC) can be used. The tensile/flexural modulus of elasticity of the second film 305 may be 1000 to 50000 MPa, preferably, 10000±1000 MPa. In addition, the thickness of the second film 305 may be 50 to 150 μm, preferably, 100±10 μm.

In this case, in order to additionally absorb shock, a third film 306 having a low strength may be inserted between the second film 305 and the polarizer 302 .

The third film 306 is a low strength film and may be of substantially the same material and thickness as the first film 304 .

The third film 306 with low strength additionally absorbs (eliminates) the impact and also serves as a protective substrate for the polarizer 302 .

Furthermore, in the first polarizing plate 301 according to the third exemplary embodiment of the present disclosure, in order to absorb external shocks more effectively, a bonding agent 309 or a first to third films 304 , 305 and 306 is interposed between the first to third films 304 , 305 and 306 . An adhesive 308a and a second adhesive 308b.

In this case, the thickness of the bonding agent 309 is about 5 to 25 μm and the bonding agent has a very low stiffness so that it acts as an impact-absorbing cushion layer. However, due to insufficient impact dispersion, the binder is not conducive to inhibiting damage to the underlying layer.

Therefore, a bonding agent 309 is interposed between the second film 305 having a high strength and the underlying third film 306 having a low strength, so that the impact dispersed by the second film 305 having a high strength is diffused to the lower layer When used as a cushion layer to reduce the absolute amount of impact.

In addition, the thickness of the first adhesive 308a and the second adhesive 308b is about 1 to 3 μm, and the first adhesive 308a and the second adhesive 308b have high rigidity and high hardness, so that dispersion is facilitated Impact but disadvantageous in breaking.

Therefore, the first adhesive 308a is interposed between the first film 304 having a low strength and the second film 305 having a high strength as the uppermost layer, and is advantageous in exhibiting the first film 304 having a high hardness Hardness properties. In addition, the first adhesive 308a is beneficial to increase the strength of the second film 305 having high strength, and suppress direct damage due to impact.

The second adhesive 308b may be interposed between the underlying third film 306 of low strength and the polarizer 302 and facilitate control of the tensile stress expression of the polarizer 302 . However, when there is concern about damage to the underlying layer, a bonding agent can be used instead of the second adhesive.

The polarizing plate and the display device having the polarizing plate according to the exemplary embodiments of the present disclosure may also be described as follows:

According to an exemplary embodiment of the present disclosure, a polarizing plate includes a polarizer and a first film having a low intensity and a second film having a high intensity above the polarizer, wherein the first film is on the uppermost layer, and the The second film is located below the first film, and the first film has a lower strength than the second film.

The first film and the second film may be alternately laminated multiple times over the polarizer.

The polarizing plate may further include a third film interposed between the second film and the polarizer, and the third film may have lower strength than the second film.

The first film may absorb (attenuate) the external shock to transmit the damped shock to the lower portion, and the second film may disperse and absorb the external shock damped by the first film.

The first film may be configured from a low-strength and high-hardness film.

The first film may be configured of any one of triacetate cellulose (TAC), acrolein-based, polyethylene terephthalate (PET), and cycloolefin polymer (COP).

The tensile/flexural modulus of elasticity of the first film may be 10 to 500 MPa, preferably, 100±10 MPa.

The second film may be configured of any one of polyimide (PI), tempered acyl, and polycarbonate (PC).

The tensile/flexural modulus of elasticity of the second film may be 1000 to 50000 MPa, preferably, 10000±1000 MPa.

The polarizing plate of the present disclosure may further include: an adhesive interposed between the second film and the third film.

The polarizing plate of the present disclosure may further include: a first binding agent interposed between the first film and the second film.

The polarizing plate of the present disclosure may further include: a second bonding agent interposed between the third film and the polarizer.

According to an exemplary embodiment of the present disclosure, a display device includes a display panel in which a polarizing plate is attached on a first substrate.

The display device of the present disclosure may further include: an additional adhesive interposed between the polarizing plate and the display panel.

While many details have been described in the above description, the details do not limit the scope of the present disclosure, but rather should be construed as examples of exemplary implementations. Therefore, the present disclosure should be determined not by the above-described exemplary embodiments, but by the claims and their equivalents.

Claims (14)

1. A polarizing plate comprising:

a polarizer;

a first film and a second film over the polarizer, wherein the first film has a low strength and the second film has a high strength; and

a third film interposed between the second film and the polarizer and having a lower strength than the second film,

wherein the first film is positioned on the uppermost layer, and the second film is positioned below the first film,

wherein the first film has a tensile or flexural modulus of elasticity of 10MPa to 500MPa,

wherein the second film has a tensile/flexural modulus of elasticity of 1000MPa to 50000 MPa.

2. The polarizing plate of claim 1, wherein the first and second films are alternately stacked a plurality of times over the polarizer.

3. The polarizing plate of claim 1, wherein the first film attenuates external impacts to transmit the attenuated external impacts to a lower portion, and the second film disperses and absorbs the external impacts attenuated by the first film.

4. The polarizing plate of claim 1, wherein the first film has a higher hardness than the second film.

5. The polarizing plate of claim 1, wherein the first film is configured of any one of triacetyl cellulose TAC, acryl, polyethylene terephthalate PET, and cyclic olefin polymer COP.

6. The polarizing plate of claim 1, wherein the first film has a tensile or flexural modulus of elasticity of 100 ± 10 MPa.

7. The polarizing plate of claim 1, wherein the second film is configured of any one of polyimide PI, tempered acyl, and polycarbonate PC.

8. The polarizing plate of claim 1, wherein the second film has a tensile or flexural modulus of elasticity of 10000 ± 1000 MPa.

9. The polarizing plate of claim 1, further comprising:

an adhesive interposed between the second film and the third film.

10. The polarizing plate of claim 1, further comprising:

a first bonding agent interposed between the first film and the second film.

11. The polarizing plate of claim 1, further comprising:

a second bonding agent interposed between the third film and the polarizer.

12. A display device, comprising:

a display panel in which the polarizing plate according to any one of claims 1 to 11 is attached on a first substrate of the display panel.

13. The display device according to claim 12, further comprising:

a further adhesive interposed between the polarizing plate and the display panel.

14. The display device according to claim 12, wherein the display panel is a liquid crystal display panel.

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